[2Bdecided]

ntscuser's passion would be more understandable if satellites didn't exist.

[ntscuser]

Originally Posted by 2Bdecided

ntscuser's passion would be more understandable if satellites didn't exist.

Satellite is useful in many situations but overall has done more harm to public service television than good.

[mossy2103]

Originally Posted by ntscuser

Satellite is useful in many situations but overall has done more harm to public service television than good.

I think that you might bet confusing the delivery system with the content providers.

[a516]

Voice of the Listener and Viewer (VLV) response to Ofcom's plans for DTT http://www.vlv.org.uk/vlv-news/annual-plan.html

[lstar337]

Originally Posted by mossy2103

I think that you might bet confusing the delivery system with the content providers.

Yes. Nothing wrong with Satellites, or satellite TV. The providers (monopoly provider) however, are another story.

[jj20x]

Originally Posted by ntscuser

Which is still one more than the first place I lived in Britain and two more than many people in Britain are able to receive properly today.

Yes but we don't really need a 1950s solution to a modern day problem. Self help relays can be set up by communities too small to be reached by PSB infill relays.

There is no reason why the VHF channels could not have been run alongside the UHF channels after 1984, either upgraded to 625-line colour with FM audio or reserved for future use.

Of course if the government hadn't botched the restart of TV broadcasts in 1946 people could have been watching 625-line or 525-line colour as early as 1955.

I'll treat decisions made in 1946 as irrelevant after 67 years...

The UK VHF network had 5 x 5Mhz channels in Band I and 8 x 5 MHz channels in Band III. To "upgrade" these to 625 line colour would need 8MHz channels, so only 3 channels in Band I and 5 in Band III. A total of 8 channels. Nationally, that could have only supported 1 channel with regional variations. There were 46 channels available on UHF, which was more than adequate. Maintaining a national network of VHF transmitter sites for 1 channel would have been far too expensive.

In any event, Band III has now been reassigned to DAB, and Band I wasn't even included in the specification for DVB-T.

I regard any business which is licensed to use frequencies previously reserved for public service broadcasting as being 'gangsters'

Then you will be happy about Band III still being used for public service DAB.

Band I is largely used, nowadays, by the military and the met office for wind radar stations. I'm not sure how they fit into your description of "gangsters".

I thought it was clear from the table in the link I posted that I was referring to the proposed new COMs 7 and 8.

The COM 7 and COM 8 layers were agreed internationally, to give the UK a possible 8 multiplexes, 9 with the national SFN. The PSB multiplexes currently use 9 tiers of (groups of 3) channels nationally, with the COM muxes fitted in between them where space is available regionally.

Reallocating the 700MHz band would mean that only 6 tiers of 3 channels were available to allow the current regional PSB networks to continue. There would no longer be any room to insert the COM muxes between the PSB ones.

Therefore the existing COM muxes would be forced into the space reserved at 600 MHz for COM 7 and COM 8 and the national SFN (COM 9) plus channels unused in the PSB tiers (ch 29/30 and channel 48).

At best that gives only 3 tiers of 3 channels to the COM muxes. That couldn't match the coverage of the existing COM muxes using DVB-T, so the COM muxes will have to be converted to DVB-T2 to allow neighbouring transmitters to operate as SFNs.

The temporary use of COM 7 and COM 8 is just to encourage users to upgrade their TV equipment to DVB-T2, in the hope that the majority will have DVB-T2 should 700 MHz be reallocated.

Far from being plum frequencies, the 600 MHz band will be used to attempt to squeeze the COM muxes into 3 tiers while the PSB muxes get exclusive use of 6 tiers.

But one or two multiplexes with decent reception is better than none. I speak from experience as up until a couple of years ago I was only able to receive one multiplex but it carried almost all of the programmes I was interested in at the time so it was no great hardship.

Converting VHF to 8 MHz bandwidth channels wouldn't have given enough capacity for 2 multiplexes with the current regional structure (VHF regions were larger than the existing UHF regions). We would have been lucky to fit a single multiplex onto VHF nationally.

As Band III is now used for DAB and Band I isn't a part of the DVB-T spec, it isn't even possible.

[jj20x]

Originally Posted by reslfj

It is very expensive to request new VHF aerials, for just one VHF mux (with only 7/8 UHF capacity).

Although Ireland used full capacity 8 Mhz channels on Band III.

VHF aerials are also large and unattractive and not many people would want to have an antenna farm on their chimney.

[jj20x]

Originally Posted by 2Bdecided

ntscuser's passion would be more understandable if satellites didn't exist.

It seems like nostalgia for a time before satellite delivery existed.

[chrisy]

Originally Posted by jj20x

VHF aerials are also large and unattractive and not many people would want to have an antenna farm on their chimney.

There's a house near me like that, it even has one of those big H aerials on it (I think for band I VHF?).

New Band III VHF aerials for DAB are quite small, I don't think anybody will complain about using those for TV.

[jj20x]

Originally Posted by chrisy

New Band III VHF aerials for DAB are quite small, I don't think anybody will complain about using those for TV.

True, Band III aerials are smaller than the Band I version. The size depends on the number of elements and how directional it is required to be. Not a problem for DAB, it largely uses SFNs. Local multiplexes often use different sites to the national multiplexes, so small, omni-directional aerials are the norm.

High powered VHF TV stations cover large areas with limited channel availability. The aerials used are usually the larger, more directional models designed to reject any rogue signals from other regions operating co-channel.

[ntscuser]

Originally Posted by jj20x

Yes but we don't really need a 1950s solution to a modern day problem.

My point was that there was only one channel when our TV was made and we were perfectly happy with it. I don't know how this modern obsession with multiple channels filled almost entirely with crap came about.

Originally Posted by jj20x

I'll treat decisions made in 1946 as irrelevant after 67 years...

The point is that decision had a knock on effect for many decades afterwards.

The wartime recommendation (never implemented) was that broadcasts resume on 525-lines, there being hardly any 405-line sets still working by 1946.

The decision to switch from 405-lines VHF to 625-lines/UHF/colour wasn't made until 1962 and even then not fully implemented until 1969.

It is unlikely such a decision would have been made if the earlier recommendation to adopt 525-lines had been implemented in 1946.

Just one botch-up after another as with every decision made since.

Originally Posted by jj20x

Then you will be happy about Band III still being used for public service DAB.

I'm happy it's being used for a public service of some kind. DAB itself I consider of waste of time.

Originally Posted by jj20x

Band I is largely used, nowadays, by the military and the met office for wind radar stations. I'm not sure how they fit into your description of "gangsters".

Unless I was grossly misled by an article in the technical press at the time Band I licenses were granted to two-way radio operators in the private sector. There was also a suggestion in the technical press that a) 405-line transmissions were being deliberately degraded in order to force people onto UHF and b) That VHF transmissions were shut down prematurely so that part of the spectrum could be used by the private sector. Experience since suggests those suspicions were probably correct.

[joshua_welby]

Originally Posted by ntscuser

My point was that there was only one channel when our TV was made and we were perfectly happy with it. I don't know how this modern obsession with multiple channels filled almost entirely with crap came about.

It came about in the 1960's-1970's with the Launch of BBC2, then in 1985 with the launch of Channel 4, then in 1997 with the launch of Channel 5 and then finally with OnDigital in Late 1998,
why we need so many channels is beyond me, I would not go back though because I like my Documentaries and News for example

[jj20x]

Originally Posted by ntscuser

My point was that there was only one channel when our TV was made and we were perfectly happy with it. I don't know how this modern obsession with multiple channels filled almost entirely with crap came about.

I think you would have a difficult time convincing many of the posters on here about that. Most seem to want more and more.

The point is that decision had a knock on effect for many decades afterwards.

Indeed but there's not much that can be done about the late arrival colour after the event, which is why I said it was irrelevant. You are right that mistakes have been made and will probably continue to be made.

I'm happy it's being used for a public service of some kind. DAB itself I consider of waste of time.

It was far too slow to gain a decent share of the audience and when it did, the standards used were already out of date. It would probably be a good idea to use the rest of Band III to introduce DAB+ and eventually phase out the existing DAB services.

Not introducing DAB+ now could probably be described as yet another mistake by the powers that be.

Unless I was grossly misled by an article in the technical press at the time Band I licenses were granted to two-way radio operators in the private sector. There was also a suggestion in the technical press that a) 405-line transmissions were being deliberately degraded in order to force people onto UHF and b) That VHF transmissions were shut down prematurely so that part of the spectrum could be used by the private sector. Experience since suggests those suspicions were probably correct.

It's difficult to tell from the spectrum allocation, the band doesn't seem to be very heavily used at all. There is a relatively minor allocation to PMSE devices, which would probably be largely used by broadcasters. It's possible that the 2 way radio equipment used in the late 80s has become obsolete and been replaced with equipment using higher frequency bands.

[jj20x]

Originally Posted by joshua_welby

It came about in the 1960's-1970's with the Launch of BBC2, then in 1985 with the launch of Channel 4, then in 1997 with the launch of Channel 5 and then finally with OnDigital in Late 1998,
why we need so many channels is beyond me, I would not go back though because I like my Documentaries and News for example

Actually it came about with the Television Act 1954 and the introduction of ITV in 1955.

We have a large amount of channels to create niche audiences to make it easier to target advertising at the correct demographic.

[Winston_1]

Originally Posted by jj20x

The UK VHF network had 5 x 5Mhz channels in Band I and 8 x 5 MHz channels in Band III. To "upgrade" these to 625 line colour would need 8MHz channels, so only 3 channels in Band I and 5 in Band III. A total of 8 channels. Nationally, that could have only supported 1 channel with regional variations. There were 46 channels available on UHF, which was more than adequate. Maintaining a national network of VHF transmitter sites for 1 channel would have been far too expensive.

625 line colour can use 7MHz channels and did in mainland Europe, Asia and Australia giving a total of 11 channels. However the argument still applies.

[Winston_1]

Originally Posted by ntscuser

The wartime recommendation (never implemented) was that broadcasts resume on 525-lines, there being hardly any 405-line sets still working by 1946.

Good job that didn't happen. 60Hz field rate, 50Hz mains supplies, crappy old sets with poor smoothing, the 10Hz flicker would have turned the viewers insane.

[2Bdecided]

Originally Posted by Winston_1

Good job that didn't happen. 60Hz field rate, 50Hz mains supplies, crappy old sets with poor smoothing, the 10Hz flicker would have turned the viewers insane.

I wonder if they considered 60Hz mains too? Mains frequencies (and voltages) were all over the place back then.

Would have made any alignment with Europe a real pain (unless they went the same way), but would have saved messy standards conversion for USA-sourced content. Cheaper equipment. Earlier colour. Lower quality.

Cheers,
David.

[DX30]

Originally Posted by ntscuser

Wot, you mean the same way the utility companies charge poor people less for gas, water, electricity, etc?

You mean like social tariffs?

http://www.consumerfocus.org.uk/get-...social-tariffs

http://www.confused.com/gas-electric...o-fuel-poverty

Originally Posted by ntscuser

When did that happen?

From memory the 2008 budget, but I may be wrong.

[jj20x]

Originally Posted by Winston_1

625 line colour can use 7MHz channels and did in mainland Europe, Asia and Australia giving a total of 11 channels. However the argument still applies.

I am aware that 7MHz was used in Europe but based my comment on UK standards rather than European standards. I'm sure you are aware that Ireland also used VHF but with 8MHz channels.

It still wouldn't be 11 channels. There was 25MHz total bandwidth in the UK Band I allocation 25/7 = 3.5, so still only enough room for 3 channels. There was 40MHz total bandwidth within the UK Band III allocation, 40/7 = 5.7, a maximum of 5 channels. Using 7MHz rather than 8Mhz in the ranges formerly allocated in the UK wouldn't change the number of channels available, there would still only be 8 channels. (Probably 5 in reality, digital television in Band I suffers from impulse noise, so may not be a good choice.)

I appreciate that the VHF bands in Europe used a wider range of frequencies than the UK, However, the discussion was about reusing pre-existing spectrum, not about expanding it.

[jj20x]

Originally Posted by Winston_1

Good job that didn't happen. 60Hz field rate, 50Hz mains supplies, crappy old sets with poor smoothing, the 10Hz flicker would have turned the viewers insane.

Indeed.

[jj20x]

Originally Posted by 2Bdecided

Would have made any alignment with Europe a real pain (unless they went the same way), but would have saved messy standards conversion for USA-sourced content. Cheaper equipment. Earlier colour. Lower quality.

I remember several years ago, when we had friends visiting from the USA. They commented about the quality of the TV pictures over here and how it was much better than in the USA.

[alanwarwic]

With the supposed 'dash for cash' in selling the airwaves not going as expected maybe there is hope for more Freeview long term.

Gifting a few extra bits for established station use would improve things.

[jj20x]

Originally Posted by alanwarwic

With the supposed 'dash for cash' in selling the airwaves not going as expected maybe there is hope for more Freeview long term.

Possibly, although it pretty much depends on what happens in Europe as a whole.

[reslfj]

Originally Posted by jj20x

Possibly, although it pretty much depends on what happens in Europe as a whole.

DTT is not limited in the UK by lack of spectrum but by the cost of running more TV channels and the limited demand for more than the ~40 channels currently available.

You can of course not continue to use the current very outdated technology - DVB-T/MPEG2.

Lars

[jj20x]

Originally Posted by reslfj

DTT is not limited in the UK by lack of spectrum but by the cost of running more TV channels and the limited demand for more than the ~40 channels currently available.

You can of course not continue to use the current very outdated technology - DVB-T/MPEG2.

It's not limited at the moment but there's not much room for expansion as HD becomes the norm. Clearly not likely to happen in the short term but possibly in the longer term. Demand for DTT spectrum could possibly increase at a time when more of it is reallocated to 4G/5G.

Unfortunately, DVB-T will probably continue for quite some time on the PSB muxes. It would be very difficult to convince the masses to replace equipment so soon after DSO. We are left playing catch-up, when DVB-T2 equipment is owned by the majority of viewers, DVB-T3/HEVC will probably be available.